Etiology and Outcome of Diffuse Acute Infectious Bronchiolitis in Adults

Abstract

The three most common etiologies of DAIB in the studied adults were M. pneumoniae, influenza virus, and H. influenzae. None of the patients with DAIB developed postinfectious bronchiolitis obliterans.

Relationship Between Clinical Features and Computed Tomographic Findings in Hospitalized Adult Patients With Community-Acquired Pneumonia

“…28 In a previous study, the rate of diffuse bronchiolitis was reported to be 1.2% among community-acquired lower respiratory tract infections. 19 The difference between this rate and the value found in the present study for the bronchiolitis pattern is explained by the different definitions used. In the present study, bronchiolitis was defined as either the presence of centrilobular nodules or a tree-in-bud pattern in most lesions with or without GGO or consolidation in the present study, whereas, in the previous study, diffuse acute infectious bronchiolitis was defined as multiple centrilobular nodules in 4 or more lobes.…”

“…28 In the present study, more than 40% of cases in the bronchiolitis group were caused by M. pneumoniae, which concurs with the findings of a previous study, in which M. pneumoniae was determined to be the most common pathogen of diffuse acute infectious bronchiolitis in adults. 19 Interestingly, common CAP pathogens, such as C. pneumoniae, S. pneumoniae and K. pneumoniae, also cause a bronchiolitis pattern. The mechanisms responsible for centrilobular nodules or tree-in-bud pattern in some patients and consolidation or GGO in others can be explained by the up-or down-regulations of host cell-mediated immunity, respectively.…”

“…In the present study, bronchiolitis was defined as either the presence of centrilobular nodules or a tree-in-bud pattern in most lesions with or without GGO or consolidation in the present study, whereas, in the previous study, diffuse acute infectious bronchiolitis was defined as multiple centrilobular nodules in 4 or more lobes. 19 However, no previous study has addressed the clinical manifestations of the bronchiolitis or bronchiolitis-predominant CAP. As expected based on published findings, 19,30 our bronchiolitis group exhibited a clinically less severe form of CAP characterized by lower levels of inflammatory markers and the absence of complicated parapneumonic effusion or empyema.…”

“…19 However, no previous study has addressed the clinical manifestations of the bronchiolitis or bronchiolitis-predominant CAP. As expected based on published findings, 19,30 our bronchiolitis group exhibited a clinically less severe form of CAP characterized by lower levels of inflammatory markers and the absence of complicated parapneumonic effusion or empyema. Data are presented as n (%).…”

“…In CAP, pure or nearly pure GGO lesions are uncommon regardless of causative pathogens, 16,18 and a CT finding multiple centrilobular nodules is also rare. 19 We hypothesized that the clinical manifestations of patients with CAP are related to CT findings, and thus, we compared the clinical features and microbiologic data of CAP patients classified based on CT findings.…”